Hysteria by Terry Johnson at Cambridge Arts Theatre until Saturday, September 8.

A MAN who never made mistakes never made anything. Sigmund Freud was a pioneer of putting people on a couch so of course he didn’t always get it right.

Hysteria by Terry Johnson at Cambridge Arts Theatre until Saturday, September 8.

A MAN who never made mistakes never made anything. Sigmund Freud was a pioneer of putting people on a couch so of course he didn't always get it right.

Not only were some of his diagnoses plain wrong, he wasn't to know that simply explaining feelings didn't stop them. It validated them.

This is a funny and fascinating play, a powerful piece, written and directed by Terry Johnson. The first half could be confused with a Whitehall farce, people coming in and out of doors, dropped trousers. A Freud with perfect comic timing, tells elaborate lies thought up on the spot to wriggle out of a situation, while he pushes one person in a closet to hide them from another. It was absurd and the audience loved it....though I wondered why I was watching a revived Brian Rix when I had come to see an illuminating piece about the father of psychoanalysis.

Then, the mood changes. Sharply. We have seen Freud at the end of his life being visited at his home in Hampstead by Salvador Dali and a strange young woman. Each is vying for his attention, meanwhile, Freud is dying and being treated with morphine by his doctor. Neither he nor we are quite sure what is real. The finale is a shocking whirlwind created by designer Lez Brotherston, lighting designer Paul Pyant and sound designer Gareth Owen.

This is a tour de force, reminiscent of an opera because it travels through so many genres, first the comedy, then a whodunit, then high drama. Antony Sher is magnificent as Freud giving an understated and inspired performance. His Freud is an avuncular man you feel you could reach out and touch.

Will Keen is an adorable Dali. His is a joyous comic role performed deftly and with panache. It has everything but the cartwheels. Perhaps he will throw a few of those in at the end of the run.

Indira Varma has at least three roles in one character as the young woman who arrives in the rain one night, knocking at the French windows to Freud's study begging him to see her. She challenges his early judgement and his motives for a change of heart.

In 1938, Freud, his wife and children, his grandchildren and his household staff escaped from Nazi Vienna to live in England. His study in Berggasse was recreated in the house in Hampstead, where Freud, already dying of cancer, was befriended by the London literati. However, his three elderly sisters were refused visas to leave and died in concentration camps.

Terry Johnson has neglected nothing and pulls no punches. This play has laughter, intrigue and horror. It is a human being.